Finally, a rapidly progressive descending weakness or paralysis occurs. Respiratory muscle paralysis and subsequent death may occur.
[8, 25] Autonomic dysfunction may lead to orthostatic hypotension, urinary retention, or constipation.

Because the toxin affects only motor and autonomic systems, sensation and mentation remain intact. Patients are usually afebrile.

Wound botulism

Except for the prerequisite history of a wound, this type of botulism presents in the same way as food-borne botulism. The diagnosis of wound botulism should be suspected in any patient with a contaminated wound that presents with neuro-muscular weakness, especially if there is bulbar involvement.
[14] Also, wound botulism, as compared to the other types of botulism, is much more like to cause fever.
[14]

Wound botulism is the least common type of botulism and may follow a penetrating or blunt injury. Recurrent wound botulism has been reported in injection drug users.
[26]

The incubation period is 4-14 days.

Infant botulism

The incubation period is 2-4 weeks. The peak age of incidence is 2-4 months.

Constipation is the usual presenting symptom, often preceding motor function symptoms by several days or weeks.

Other signs of autonomic dysfunction usually present early as well, including those mentioned above. Gag reflexes are frequently impaired, which can lead to aspiration if the airway is unprotected.

Infants with botulism are afebrile, suck poorly, and are lethargic and listless. They often are described as being floppy.
[9] Constipation is almost always the first sign of infant botulism.
[27] Constipation, poor feeding, ptosis, facial and generalized weakness are considered to be the classical signs of infant botulism.
[15] They develop the same descending weakness and paralysis that occurs in those with food-borne disease. About 25% of babies with infant botulism present with hypoventilation,
[13] but 60% of patients with infant botulism may develop hypoventilation, and require ventilatory support as the disease progresses.
[8] Awareness of the symptoms of botulism, and a high degree of clinical suspicion is needed to make a prompt diagnosis of infant botulism and prevent death.
[25] Initially, infant botulism may be confused with an infection or may exist concomitantly with a respiratory infection, and if the potentially fatal diagnosis of infant botulism is not thought of, it willbemissed with dire consequences.
[27] Breastfeeding may protect infants from lethal fulminant infant botulism, but exclusive breastfeeding is a risk factor for the disease, presumably because the relatively pristine bowel flora of the exclusively breastfed infant is more permissive for spore germination and toxin production.

Frequencies of the most common symptoms and signs of food-borne and wound botulism are as follows:

Dysphagia - 96%

Dry mouth - 93%

Diplopia - 91%

Dysarthria - 84%

Extremity weakness - 73%

Constipation - 73%

Blurred vision - 65%

Nausea - 64%

Dyspnea - 60%

Vomiting - 59%

Abdominal cramps - 42%

Diarrhea - 19%

Frequencies of the most common symptoms and signs of infant botulism are as follows:

Poor ability to suck - 96%

Poor head control - 96%

Hypotonia - 93%

Weak crying - 84%

Constipation - 83%

Lethargy - 71%

Facial weakness - 69%

Irritability - 61%

Hyporeflexia - 52%

Sluggish pupils - 50%

Respiratory difficulty - 43%

It is important to maintain a high degree of suspicion of the diagnosis of infant botulism, in any infant presenting with acute acquired hypotonia.
[13] The history of constipation, hoarse cry, progressive weak suck, and symmetric descending weakness, and the physical exam findings of bilateral extremity weakness, truncal weakness, marked head lag and decreased gag reflex point very strongly to the diagnosis of infant botulism.
[13] The combination of ptosis, bilateral facial weakness and poor respiratory effort should make the physician very suspicious of the diagnosis of infant botulism complicated by respiratory failure.
[27]